Due to its advantages of high energy density, long cycling life, low cost, beneficial for the light weight of electric vehicles and so on, ternary cathode material has become the mainstream choice of electric vehicle drive power, and there will be a greater market space in the future.
At present, most of the ternary materials in the market are secondary spherical particles which are sintered by precursors obtained by coprecipitation. In the process of coating and cold pressing, the secondary spherical particles are easily broken, the doping layer is destroyed, and the primary particles without doping easily lead to the battery high-temperature storage swollen, and affect the cycle performance. During the process of high temperature cycling, with the increase of cycle number, the primary particles of agglomerated form may be separated, which leads to the increase of internal resistance, the increase of side effect in internal battery, and the rapid decay of the cycle. Thus, there is a need to develop new lithium ion cathode material.
Chinese patent Application No. 201410327608.5 disclosed a high voltage single crystal nickel cobalt lithium manganate cathode material and preparation method thereof. Doped nickel-cobalt-manganese hydroxide precursors were prepared by co-precipitation method, then the precursors were pre-calcined at high temperature to obtain nickel-cobalt-manganese oxide. After mixing with the lithium salt and the doping element, the nickel-cobalt-manganese oxide was sintered and coated to obtain the high voltage single crystal cathode material. Patent CN201410054279.1 disclosed a preparation method of high-density nickel cobalt lithium manganate cathode material. The ternary precursor was prepared by co-precipitation method, then the precursor was pulverized at high speed to obtain single crystal ternary precursor. After mixing with the lithium salt, the single crystal ternary precursor was sintered and pulverized to obtain single crystal ternary cathode material. Patent CN201110278982.7 disclosed a cathode material for lithium ion battery and lithium ion battery using the same. A nickel salt, a cobalt salt, a manganese salt and a single crystal morphology lithium carbonate were mixed to sinter and pulverize or a precursor of nickel-cobalt-manganese and a single crystal morphology lithium carbonate were mixed to sinter and pulverize to obtain single crystal cathode material. At the same time, the morphology of the cathode material in the observation of the scanning electron microscope is single crystal morphology rather than secondary spherical morphology.